If the problem is just occuring at the kitchen sink, it sounds to me like a bad diverter valve...the internal valve that directs water to the sprayer. Working correctly, when you use the sprayer, water from the faucet shuts off and it all goes to the sprayer...when you let off the trigger of the sprayer, water starts coming back out of the faucet. If your sink has a sprayer, I would bet this is the problem. Should be able to get a new diverter valve pretty cheap if the faucet is a name brand.